Ten games in and Activision's cultural juggernaut Call of Duty shows no signs of slowing. Even the mass departure of staff at Infinity Ward, the studio responsible for the Call of Duty formula, in 2010 appears to have little detrimental effect on the series, which continues to see rising sales.

For 2013 the developer has turned from the noise and spectacle of Modern Warfare 3 to a softer approach, basing the game on an band of covert operatives dubbed Ghosts who crouch and sneak through a series of missions set in the near future.

At the E3 conference in Los Angeles last week, Simon Parkin caught up with Infinity Ward's Mark Rubin to find out more about Riley the attack dog and how the studio aims to respond to Respawn's Titanfall, the EA-published game made by Infinity Ward's one-time founders.

Simon Parkin: What's the story with Riley, the attack dog? He appears to have become the star of your game overnight.Mark Rubin: It 's been such a surreal experience. We saw the trailer go up and literally within seconds everyone was talking about the dog. We didn't really do much in the way of promotion and had no idea that was going to happen. All of the memes and the fake twitter accounts and so on have been fantastic.

It had a strange effect at the studio. Initially everyone was excited but pretty quickly that turned into looking like deer in headlights. The team started to panic over whether we're doing the dog well enough, whether his story is strong enough. All of these things.

Has this reception changed the way in which you're going to do things at all?Well, there was this panic mode for a bit. Then we talked to the team, told them to relax and just keep doing what they're doing; not get caught up in the emotional aspects of what they were seeing on the internet. We were able to steer people back to what they were supposed to be doing.

The term 'Call of Duty fatigue' refers to the sense of ennui that can set in with yearly updates to a series. The emphasis on the dog seems like a useful way in which to counter that; something to distinguish the game from its forebears beyond a new setting or weapons. Is that fair?Yeah … But I think we're looking for that in every game we make. It's what keeps us hungry each year. We come out of a game and when we embark on the next one we know we have to do something new to keep it fresh; we have to do something to ensure it's going to be the best game we've made. It's important to keep that hunger and not rest on the Call of Duty name. I think the proof's in the pudding. Every year sales are growing.It's interesting you should say that. Call of Duty is a series built around spectacle and with every new release we sense that the spectacle has to outdo the previous game's efforts. In Modern Warfare 3 you have the Eiffel Tower collapsing, for example. Where do you go from that?We didn't do that because we felt Modern Warfare 3 had to be about spectacle.

Really?No, we did that because it fit the story we wanted to tell at the time. One of the things we're doing with this game is going back to Call of Duty 4. When we designed that game we wanted to ensure the pacing was different. So you went from all out warfare with tanks and planes to slower paced stuff like the sniper or AC-130 missions. It had this great pacing so, for this game, when we started crafting how the story would turn out it made a lot of sense to go back to that idea. Everything we've shown at E3 has been pretty much stealth. It's going to be more balanced with the ups and downs. The story will feel different because of that.

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Is that the reason you chose to focus on the Ghost Recon-style squad?Partly. It all sort of happened at the same time. It wasn't that one led to the other. Our guys think story first and in parallel we're thinking about what cool moments we're going to use in that story. Those kind of things become cards on a board and we pin them up and move them around. At that point we become like sculptors. You have this big block of granite and you begin chipping away at it to reveal the final game.

You have this concrete audience that loves Call of Duty. But more generally the FPS is the genre that attracts the most invention and iteration; it's where the vast majority of focus in modern game development occurs. How do you respond to developments in the genre that occur in rival's titles. Do you seek to incorporate their evolutions or do you keep doing what you're doing in order to keep your audience happy?What we have to do as game developers is serve our current audience. Imagine if in football they suddenly changed the rules so, instead of using your feet, you had to use your hands. If that happened nobody would want to watch football anymore.

Moreover, I don't want every game to be copying what every other game is doing. I want every team to be making its own creative statement. Call of Duty has a creative statement. For single player it's that cinematic, movie-like experience that's immersive and pinned on storytelling. It has those big moments, those summer blockbuster type trailers: the Call of Duty feel. Multiplayer has that fast, frantic addictive gameplay and that's something we wouldn't want to give up. It's what we do well. I want other studios to be doing something else, something new and fresh and cool that nobody's seen before, so I can play that while continuing to enjoy Call of Duty.

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OK but how do you stop from becoming creatively fatigued?I don't have an answer for that because I don't feel like fatigue is something we've experienced yet. We do some things in-house at the studio where we allow people to come up with stuff on their own in order to scratch that creative itch. A lot of times that idea becomes a part of the full game…Can you give an example?The survival mode in Modern Warfare 3 came from someone on their own time playing around with the game. They were doing some work with bots and created a minigame that had an RTS feel at first and then began to morph into Survival Mode. I think Zombies [game mode] was a similar thing at Treyarch. We do get chance to diverse out and all of that work either gives people new ideas or actually makes its way into the game.

What's you're guiding principle with that? How do you know when something is slightly too far to the left of Modern Warfare-ness?It's a crowd-based understanding. Everyone at the studio from the QA guys to designers to artists to coders are all hardcore players, or at very least averagely good players. As a group we keep ourselves in check. We're a democratic company. We don't have a strong top-down dictatorship. It's often up to the designers working on a level to make decisions. I can go in and give feedback, but the guy doing the work is the one who will make the ultimate call.

Why do you think a disproportionate number of video games focus upon the military shooter?I don't know … We got here and it blew up and, for consoles in particular, it became a phenomenon. I wonder if other company's think this is where the success is at. I hope they're making their games because those are the games they want to make. I'd hate to learn people are just making something that they're not honestly passionate. This is an industry entirely based upon passion.• Call of Duty Ghosts is released on PC, PS3, PS4, Xbox 360 and Xbox One in November